How to recreated:
1. Equip an elytra
2. Use a slow falling effect
3. Glide to an angle that makes the player glide the slowest to the ground (Use f3 on Y coordinates)
4. Do 360° flip until the flickering happens (it most likely happens when the wing are close after 360° flip)

Note: If you don't know how when the wings are close, just check the video when the 360° flip part.